1. Field of the Invention
The present invention relates to an electromagnetic stirring method for forming a plurality of rotating flows of a molten metal as seen in the cross section of the molten metal as it passes through a space defined by one or two yokes.
2. Description of the Prior Art
The heretofore available rotating-field type electromagnetic inductor which is used for electromagnetic stirring
(1) In the case of electromagnetic stirring of molten metal by a rotating field in a mould or a secondary cooling zone, it is impossible to form a plurality of rotating flows with a still portion retained in the same cross section of the molten metal;
(2)In the case of twin-, triple- or multi-strand pouring, it is difficult to provide a rotating-field inductor if the distance between the strands is not sufficiently large;
(3) In the case of multi-stage stirring, an equal number of inductors and power supplies are required to match the number of stages of stirring.
(4) In the case of casting steel pieces of substantial width, electromagnetic stirring conducted by a rotating-field inductor cannot be effected; and
(5) In the case of casting steel pieces of small size in a large continuous casting machine, a rotating-field inductor for the secondary cooling zone which interferes with a common dummy bar piece must be divided into two portions and provided with a lifting device.